Britain's royal family were struggling on Sunday to prevent the spread of topless photographs of Prince William's wife Catherine, after the threat of legal action failed to intimidate Irish and Italian titles.

In a fresh blow to the royals a day after they began legal proceedings against French magazine Closer, the first to publish the long lens pictures of Catherine sunbathing in her bikini bottoms, the images appeared again in Saturday's Irish Daily Star.

"There can be no motivation for this action other than greed," said a spokeswoman for Catherine and her husband, the second-in-line to the British throne.